This invention relates to certain improvements in the structures described and claimed in the Baier Pat. No. 3,209,663.
The purpose of the cover is to close a hatch, manhole or other such opening. In Baier, the cover is securely locked in place by a locking bar which is rotatable into locking position against the underside of a deck ring which receives the cover. The bar is clamped by a bolt passing through the cover and bar. Means are provided on opposite ends of the bolt for rotating it from either the outside or inside of the cover. A peripheral seal on the cover maintains a water tight and air tight joint when the cover is locked and clamped in place.